Chimney stacks covered in a mosaic of coloured ceramic tiles, on the roof of the Casa Batllo, originally built in 1877 by Emilio Sala Cortes and totally remodelled 1904-6 by Antoni Gaudi, 1852-1926, in catalan Modernisme and art nouveau style, for Josep Batllo y Casanovas, a textile industrialist, on the Passeig de Gracia in the Illa de la Discordia district of Barcelona, Catalonia, Spain. The chimney stacks are crooked to prevent backdraughts. The building is listed as a UNESCO World Heritage Site. Picture by Manuel Cohen